title: [Thermostable riboflavin kinase in the yeast Pichia guilliermondii].
abstract: It is found out when studying the process of riboflavin kinase (E.C.2.7.1.26) thermoinactivation in cell-free extracts of yeast, that the reaction of riboflavin phosphorylation in the cells of this organism are catalyzed by two enzymes one of which is distinguished by high thermal stability. The inactivation rate constant of the process of thermoinactivation (K(in)) at 90 degrees C is 11.2 x 10(-4) sec-1 for thermostable enzyme and 4.0 x 10(-2) sec-1 for another one. The enzymes are considerably distinguished by the values of activation thermodynamical parameters (delta H*, delta S*, delta P*, Eact*) of the process of thermoinactivation in the temperature range 75-90 degrees C. Thermostable and thermolabile forms of riboflavin kinases are separated under electrophoresis in polyacrylamide gel.
authors.forename: L R
authors.initials: LR
authors.lastname: Faiura
authors.forename: V S
authors.initials: VS
authors.lastname: Kashchenko
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D006358:Hot Temperature; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry*; D010843:Pichia / Q000201:enzymology*; D013816:Thermodynamics
chemical_list: D017853:Phosphotransferases (Alcohol Group Acceptor); C022532:riboflavin kinase
vernacular_title: Termostabil'na ryboflavinkinaza u drizhdzhiv Pichia guilliermondii.